As erratic-armed Viking backup Joe Webb displayed Saturday night, any NFL quarterback can fling a football to Saskatchewan.

Rockets arms are a dime a dozen, but the ability to air it out with accuracy separates the sub-par from the sensational.

In his first NFL start, Colin Kaepernick’s quickly showed off this quality. His perfectly placed 57-yard rocket to a well-covered Kyle Williams down the right sideline was San Francisco’s longest pass play of the season. Looking back, it was also a compelling signal that Kaepernick was wresting the starting job from Alex Smith on that Monday night against the Bears.

Really, there’s no way Smith – or a host of NFL quarterbacks – can make that throw.

On Saturday, Kaepernick will oppose Green Bay’s Aaron Rodgers, who can make that throw and many more. In fact, by one metric, Saturday’s divisional-playoff game will pit the NFL’s most accurate deep-ball passers.

Among quarterbacks with at least 30 passes that have traveled 20-plus yards downfield, Kaepernick ranks first with an accuracy percentage of 60.6, according to Pro Football Focus. Second? That would be Rodgers at 53.2.

On Saturday, they will attempt their long lasers against above-average secondaries.

Quarterbacks had a 76.8 rating against the Packers, the fourth-lowest in the NFL. The 49ers held quarterbacks to a 78.0 rating, which ranked sixth. Both teams allowed seven passes of at least 40 yards, which was tied for 10th in the league.

Here’s a look at the NFL most accurate deep-ball passers, per PFF (Note: Alex Smith had an accuracy percentage of 50.0, completing 9 of 18 such passes with no drops):

1. Colin Kaepernick, 49ers

Attempts of 20-plus yards: 33

Completions: 19

Drops: 1

Accuracy percentage: 60.6

2. Aaron Rodgers, Packers

Attempts of 20-plus yards: 62

Completions: 26

Drops: 7

Accuracy percentage: 53.2

3. Peyton Manning, Broncos

Attempts of 20-plus yards: 72

Completions: 33

Drops: 5

Accuracy percentage: 52.8

4. Cam Newton, Panthers

Attempts of 20-plus yards: 63

Completions: 28

Drops: 5

Accuracy percentage: 52.4

5. Robert Griffin III, Redskins

Attempts of 20-plus yards: 36

Completions: 16

Drops: 2

Accuracy percentage: 50.0

** The 49ers signed linebacker Nate Stupar, a seventh-round of the Raiders in 2012, to the practice squad.

Stupar (6-2, 240) was released by the Raiders on Sept. 12. He was signed to Eagles practice squad on Nov. 19 and spent the rest of the regular season in Philadelphia.

A native of State College, Pa., Stupar started 16 games in his career at Penn State. His brother, Jonathan, was a tight end for the Bills from 2009-10. His uncle, former NFL quarterback Jeff Hostetler, was a 15-year NFL veteran.